A buff polishing process is known as a processing method for smoothing an outer surface (also referred to as a “resin-coated surface”) of a resin coating covering the surface of, for example, a body of an automobile. The buff polishing process is a processing method of polishing the surface of a polishing object by pressing a rotating cloth buff, for example, against the polishing object with a polishing composition interposed between the buff and the polishing object.
The polishing composition used in the buff polishing process contains abrasives (abrasive grains) that is exemplified by alumina particles (see, for example, PTLs 1 to 3).
Such a conventional buff polishing process using a polishing composition containing abrasives, however, cannot sufficiently reduce undulation of a resin-coated surface in some cases. In addition, the conventional buff polishing process using the abrasives containing the abrasives causes polishing flaws on the polished resin-coated surface in some cases. This can cause a failure in finishing with an excellent glossy resin-coated surface.